In the title compound, C(24)H(28)N(2)O(4)S, the dihedral angle between the phenol ring and the thia-zole ring system is 10.6 (1)°, and the trimethoxy-phenyl group is approximately perpendicular to the thia-zole ring, the dihedral angle being 84.7 (2)°. There is a strong intra-molecular hydrogen-bonding inter-action between the Schiff base and the hydr-oxy group.